From Thermionic Studios
Jump to: navigation, search

Music performers all too often operate under a common misperception. That common misperception is that their guitar doesn't sound right, their keyboard doesn't sound right, their bass doesn't sound right. While operating under this misconception, pickups are swapped out, different string gauges attempted, new amps purchased, new instruments are built of different tonewoods, different effects and pedals introduced, etc...

In many cases, all this expense could be avoided if the musician looked at the possibility of swapping out the speakers that s/he is unknowingly displeased with. In most cases, swapping out speakers makes the greatest difference in an electric musician's tone - far more difference than in changing pickups or in getting a new instrument made of a different tonewood.

Sure - all of the elements that make up the signal chain matter. Body woods, fretboard woods, pickups, potentiometers, amps, etc. They all matter. However in far too many cases, (and to the glee of the builders of musical instruments) players end up paying to change out things that matter far less than speakers. Next time you are unhappy with your sound, don't immediately think you need a new graphic equalizer or a new pickup. Instead consider changing your speakers.

Speaker Sizes

8 inch

We don't know of any famous musician who routinely uses eight inch speakers for either the day-to-day creation of new music or for the performance and presentation of such music. There are always occasions where an artist will use an eight inch speaker in the process of creating a new sound, but it's more for the novelty factor.

The other reason why an artist would use eight inch speakers is because that happens to be the size speaker that has been installed in the practice amp that the artist is using. Finding eight inch speakers isn't uncommon. Finding eight inch speakers that can withstand 100 watts at 16 ohms and that are operating at 103 dB of efficiency are practically unheard of.

10 inch

Ten inch speakers are notable for having been installed in early Fender Tweed Era amplifiers. The earliest precursor to the Marshall 100-watt stack, interestingly enough, was the 1957 Fender Bassman combo amp with 4 ten inch Jensen speakers. However, in most cases, especially in music that is being made today, ten inch speakers are most commonly associated with bass rigs.

12 inch

Twelve inch speakers are the most common guitar speaker. We are unaware of a company that makes electric guitar speakers that does not make a twelve inch speaker. Just as "conventional paper" is the standard material for speaker cones, so are twelve inch speakers the standard size for music (and most specifically for guitar) amplification.

15 inch

Fifteen inch speakers are almost exclusively the domain of electric bass and keyboard players. Occasionally, a synthesizer or keyboard player will use a 15-inch speaker, this is done to emphasize the bass frequencies. Fifteen inch speakers, due to their increased size, have an easier time of turning the electrical signal from the amplifier into clear bass response.

Speaker Types


Aluminum speaker cones used by musicians are most often identified with the Hartke speaker company. The aluminum cone is formed from a thin sheet of aluminum that is pressed against a conical shape and forms a thin cone. This thin cone is then connected to a speaker motor. By "thin" we mean usually thinner than the thickness of an aluminum can. Aluminum cones are known to be very efficient as they have a much higher tensile strength than paper. The higher tensile strength allows them to be thinner. That thinner quality results in the speaker motor having to move less mass and therefore making them more efficient. This increased efficiency also makes them very loud. The main concern with aluminum cones is that the higher tensile strength of the aluminum substrate results in a higher corresponding rigidity. The combined increased efficiency and rigidity causes aluminum speaker cones to wear out more quickly than other materials.

As a result, this also tends to cause aluminum speakers to be considered "shrill" or "tinny-sounding". Not only is the cone more efficient, but because the speaker has a thinner and more rigid cone (as compared to paper), it tends to send out more high frequencies. For musicians, aluminum cones are typically only found for bass, or public address systems. Aluminum cones are favored for bass as they can be described as bringing snap to an otherwise "woody" or muffled instrument.

Outside of music performance, the most common use everyday of aluminum cone speakers is in car audio systems.

Conventional Paper

Conventional paper is just what it sounds like - the standard medium for building speaker cones. Chances are, the speaker cabinets you see at music shows are housing the standard, conventional, black paper speakers. Conventional speakers are the yardstick against which every other speaker material is judged.


Hemp fiber is possibly the newest material to be introduced in the manufacture of speaker cones. The making of speaker cones of hemp is not without controversy as hemp is the fibrous part of the cannabis plant. Hemp is very durable as a fiber. Rope and paper have been made for hundreds of years with hemp. Hemp speaker cones tend to be very durable as the hemp material has anti-shearing or anti-tearing properties. However, hemp is also sometimes criticized as a coning material that prevents high-frequencies from getting out from the amp accurately. This results in a "wooliness" or muffled quality emitting from the speakers. We believe that should the market continue to reward amp and speaker builders for their use of hemp, that hemp cones will become better as more research and development is undertaken to create better sounding speakers. Ideologically, we support, and to the degree that we can, financially support the manufacture of hemp speakers. We believe that historical evidence supports the view that marijuana was made a boogeyman after the ending of (alcohol) Prohibition in 1933 so that our government could keep otherwise unneeded cops on payroll and imprison those who aren't harming anyone else. We also believe that there is adequate evidence to recommend the use of hemp in many other industrial applications. We believe this would help green our world by mitigating air pollution, and would also serve to transition us away from plants that are both slower to grow, and require many more resources to successfully cultivate, fertilize, and process into consumer products.

Plastic Film

There is no speaker company, that we're aware of, that expects musicians who are serious about their craft to use plastic film as a speaker coning material. Plastic speakers can be found in cheap transistor radios, or in the cabinets of those people who try to rip you off by approaching you and your friends in a random parking lot and telling you how they're going to give you the deal of a lifetime. "Our boss told us to just get rid of these speakers cheap". Plastic film is also typically used in the cones of "bargain" speakers that are installed in the backs of cars. Don't waste your time with plastic speakers - they're a waste of your money.

Speaker Dustcaps

The original purpose of speaker dustcaps (or "dome" in the center of the speaker cone) was to prevent dust and other particles from falling into the voice coil of the speaker.

Times changes, perspectives change, and with the change in perspective comes new opportunities. There are many sizes of speaker dust caps. There are a number of different effects that can be caused by altering a dust cap. Smaller dust caps join to the speaker cone in the higher-frequency area of the cone. There hasn't been enough research that is popularly available, so there is no set formula, however, depending on the material of the dome, the cap can either emphasize or attenuate those higher frequencies. In other words, a solid dome made entirely of acoustic foam will attenuate the high frequencies. A hollow dome made of aluminum film will cause them to jump out.

As most speaker dust caps are made of the same material as the speaker cone, a reasonable rule-of-thumb would be:

  • that a smaller cone tends to emphasize higher frequencies, and that
  • a larger dome will result in emphasizing more midrange frequencies.

No speaker dome is so large as to emphasize bass frequencies. If you want more bass, get bigger speakers, or investigate speaker cabinet porting.

Speaker Modifications

  • Weber Beam Blocker (supposed to remove high-frequency "beaminess")
  • Jay Mitchell Foam Donut (same function as the Weber Beam Blocker. Seems much better researched) [1]
  • Torn/slashed speaker cones
It's not uncommon to see ribbing in speaker cones. These ribs are not lines that radiate out from the center, rather they appear as concentric rings. When they are used, they appear near the dust covers that surrounding the center. These ribs then get larger as they expand from the center to the edges of the speaker cone. The purpose of these ribs is to physically reinforce the cone, again to prevent shear or tearing, in situations of high volume, and movement. There are different arrangements of ribbing in speakers - most cases consist of a few ribs at the outermost edges of the speaker as this is where the most movement occurs and where the ribs will least color the tone. Ribbing can also be placed around the middle of the cone to inhibit certain frequencies, or to reinforce those frequencies as desired by the manufacturer.
Rola Doping 
Doping is an applied flexible reinforcement that's placed around the edge of paper or other fiber speaker cones to help make them more stable and less prone to shear or tearing. If you look at a typical paper speaker cone and observe a darker, slicker, glossier band running around the outside edge of the cone, this is going to be the doping agent. This doping agent isn't terribly different from rubber cement, and in a pinch rubber cement can be used. The reinforcement that doping adds to a speaker cone tends to make that cone bassier when compared to the same cone undoped. Most cones, if doped, are given a "light" doping so as to minimize tone coloration. Many times, musicians and performers will prefer the tone of a doped cone over a non-doped cone, with the comment that undoped cones are too "shrill". Doping, like music and tone, pretty clearly boils down to personal taste. Make sure to listen to many kinds of speakers, each with different levels of doping to come to your own conclusion as to which tone you prefer. Here at Thermionic, depending on the speaker, we tend to prefer light doping.

Speaker Manufacturers